SPIRV-Tools/source/opt/inline_exhaustive_pass.cpp
Steven Perron 2d2a512691
Don't inline recursive functions. (#2130)
* Move ProcessFunction* function from pass to the context.

There are a few functions that are used to traverse the call tree.
They currently live in the Pass class, but they have nothing to do with
a pass, and may be needed outside of a pass.  They would be better in
the ir context, or in a specific call tree class if we ever have a need
for it.

* Don't inline recursive functions.

Inlining does not check if a function is recursive or not.  This has
been fine as long as the shader was a Vulkan shader, which forbid
recursive functions.  However, not all shaders are vulkan, so either
we limit inlining to Vulkan shaders or we teach it to look for recursive
functions.

I prefer to keep the passes as general as is reasonable.  The change
does not require much new code in inlining and gives a reason to refactor
some other code.

The changes are to add a member function to the Function class that
checks if that function is recursive or not.

Then this is used in inlining to not inlining a function call if it calls
a recursive function.

* Add id to function analysis

There are a few places that build a map from ids to Function whose
result is that id.  I decided to add an analysis to the context for this
to reduce that code, and simplify some of the functions.

* Add missing file.
2018-11-29 14:24:58 -05:00

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2.7 KiB
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// Copyright (c) 2017 The Khronos Group Inc.
// Copyright (c) 2017 Valve Corporation
// Copyright (c) 2017 LunarG Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "source/opt/inline_exhaustive_pass.h"
#include <utility>
namespace spvtools {
namespace opt {
bool InlineExhaustivePass::InlineExhaustive(Function* func) {
bool modified = false;
// Using block iterators here because of block erasures and insertions.
for (auto bi = func->begin(); bi != func->end(); ++bi) {
for (auto ii = bi->begin(); ii != bi->end();) {
if (IsInlinableFunctionCall(&*ii)) {
// Inline call.
std::vector<std::unique_ptr<BasicBlock>> newBlocks;
std::vector<std::unique_ptr<Instruction>> newVars;
GenInlineCode(&newBlocks, &newVars, ii, bi);
// If call block is replaced with more than one block, point
// succeeding phis at new last block.
if (newBlocks.size() > 1) UpdateSucceedingPhis(newBlocks);
// Replace old calling block with new block(s).
// We need to kill the name and decorations for the call, which
// will be deleted. Other instructions in the block will be moved to
// newBlocks. We don't need to do anything with those.
context()->KillNamesAndDecorates(&*ii);
bi = bi.Erase();
for (auto& bb : newBlocks) {
bb->SetParent(func);
}
bi = bi.InsertBefore(&newBlocks);
// Insert new function variables.
if (newVars.size() > 0)
func->begin()->begin().InsertBefore(std::move(newVars));
// Restart inlining at beginning of calling block.
ii = bi->begin();
modified = true;
} else {
++ii;
}
}
}
return modified;
}
Pass::Status InlineExhaustivePass::ProcessImpl() {
// Attempt exhaustive inlining on each entry point function in module
ProcessFunction pfn = [this](Function* fp) { return InlineExhaustive(fp); };
bool modified = context()->ProcessEntryPointCallTree(pfn);
return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}
InlineExhaustivePass::InlineExhaustivePass() = default;
Pass::Status InlineExhaustivePass::Process() {
InitializeInline();
return ProcessImpl();
}
} // namespace opt
} // namespace spvtools